Assuming your real worry, is the data integrity of ROM images. I'd suggest you simply checksum your ROM files (on your HDDs/DVDs), and check those checksums, against known published checksums, for those ROMs.
This was my suggestion also. To repeat – so that others can confirm or refute my suggestion –:
Do note that browsers do occasionally fail a download. This is much more common than any bad blocks issues on HDDs. These often occur because of network connectivity issues. Usually, the browser download window notes that the download was aborted, but the partial file still exists in the download folder.
So, you should be much more worried about whether the downloads succeeded or not, than about HDD badblocks.
This is also the reason why you see shaNsum files provided at download sites. For example, San Fransisco GCC 10.2.0 mirror.
The sha512.sum file contains checksums that one can compare to the downloaded files, to verify the file integrity. There are command-line commands in Linux, BSDs, Mac OS, and even Windows (PowerShell) to verify these checksums. You can use e.g. Quickhash GUI to generate these for your own files, or verify any files you have downloaded.
The idea is that before burning (a copy of your own files), you use calculate the sha512 checksums of those files.
Before burning downloaded files, you verify their sha512 checksums match.
This way, you verify that the data you are burning to the DVD is correct.
(The DVD itself has extensive error correction mechanism, and again, if the DVD degrades, you will get read errors rather than bad/broken data.)
Personally, I also burn those checksum files to the DVD, because hey, why not: verifying them on the DVD makes doubly sure the data is still intact.
Later on, when you need those files, you first re-check the files against their checksums. If the checksums still match (or the verification passes, if you use the GUI), then you can be assured that the data on the DVD is still intact. But, if the DVD is readable and copies the files without popping up error windows, the data should still be intact.
I also explained that this has worked well for me for over two decades; I tend to make a full backup of my own files at least once a year, and burn to a DVD-R (initially CD-R). (I do incremental backups more often, around once a month for stuff I don't care much about, every time after a significant change for stuff I do care about, to USB flash storage.)
I keep the DVD-R/CD-R discs shielded from natural light, because I did have one set of CD-Rs degrade in a semi-transparent storage box on a shelf in direct sunlight. I do prefer metal sheet boxes for this (like old-timey tins used for coffee and so on), but I do no other maintenance at all to them. (And I'm not even sure if it is only because I kinda like those old-fashioned painted tin boxes, and similarly painted ceramics at kitchen for storing tea and spices...)
The underlying problem here is that stating the above, even with direct links to software, and describing the procedure to checksum, verify, and re-burn copies with checksum files for later verification, will not help the asker with the underlying problem, because the underlying problem is an affliction that requires non-technical specialist help in behaviour control. You don't get rid of OCD by creating better rituals: those just provide short-term help with the symptoms.
Here, if we use germophobia as an analog, we have shown that yes, washing ones hands when coming home, before preparing food and eating, is indeed a good idea because those germs do exist. But excessive hand washing itself is a health risk; and if moving from regular hand soap to industrial cleaning agents, can be fatal. Even at a biologically/physically harmless level, as a behavioural pattern it can be a serious social barrier for interaction.
The solution is not to suggest patterns that keep the hand washing to an acceptable level, because the sufferer already knows that, but to stop the discussion on which soaps and how often to use them, and directly tell the person they need help with this, because the symptoms themselves are making that person too difficult to interact with. These are not rare problems in humans at all – even I am talking about personal experience here –, and there is absolutely no shame in seeking help with these, no more than seeking medical help when you have a broken bone. It is a known affliction, with a rather good chance of seriously alleviating the
root causes via proper therapy, not only making the person themselves happier, but also much easier for others to interact with. Win-win, in my opinion.
But it does need that gentle but firm "
Dude, stop. This is not the way." intervention.